The present invention relates to a food intake restriction device for the treatment of morbid obesity. More specifically, the invention relates to a food intake restriction device for surgical application in the abdomen of a patient for forming a stoma opening in the stomach or esophagus of the patient.
Food intake restriction devices in the form of gastric banding devices, in which a band encircles a portion of the stomach, have been used in surgery for morbid obesity to form a small gastric pouch above the band and a reduced stoma opening in the stomach. Although such a band is applied around the stomach to obtain an optimal stoma opening during surgery, some prior gastric banding devices are provided with an adjustment means enabling a minor post-operation adjustment of the size of the stoma opening. In all such prior devices, such as disclosed in U.S. Pat. No. 4,592,339, European Patent No. 0611561 and International Patent Application WO 94/27504, the adjustment means comprises an inflatable cavity in the band and an injection port in fluid connection with the inflatable cavity for adding fluid to or withdrawing fluid from the inflatable cavity. In practice, the band is made of silicone rubber which is a material approved for implantation and the fluid is a liquid such as an isotonic salt solution.
It has been found that the volume of said gastric pouch above the band increases in size up to ten times after the operation. Therefore the pouch volume during surgery needs to be very small, approximately 7 ml. To enable the patient to feed the stomach with sufficient nutrition immediately after the operation considering such a small gastric pouch, the stoma initially needs to be relatively large and later needs to be substantially reduced, as the pouch volume increases. Furthermore, the size of the stoma opening has to be gradually reduced during the first year after surgery as the gastric pouch increases in size. As indicated above, the reduction of the stoma opening using the prior art gastric banding devices is achieved by adding liquid to the cavity of the band via the injection port to expand the band radially inwardly.
A great disadvantage of repeatedly injecting liquid via the injection port is the increased risk of the patient getting an infection in the area surrounding the injection port. If such an infection would occur the injection port has to be surgically removed from the patient. Moreover, such an infection might be spread along the tube interconnecting the injection port and the band to the stomach causing even more serious complications. Thus, the stomach might be infected where it is in contact with the band, which might result in the band migrating through the wall of the stomach. Also it is uncomfortable for the patient when the necessary, often many, post-operation adjustments of the stoma opening are carried out using an injection needle penetrating the skin of the patient into the injection port.
Further, the patient may swallow pieces of food that are too large to pass the restricted stoma opening. At such an occasion the patient has to visit a doctor who can remove the food pieces, if the band design so permits, by withdrawing some liquid from the band to enlarge the stoma opening to allow the food pieces to pass the stoma. Then, the doctor has to add liquid to the band in order to restore the restricted stoma opening. These measures also require the use of an injection needle penetrating the skin of the patient, which is uncomfortable for the patient.
The invention provides an adjustable food intake restriction device which permits regular post-operation adjustments that are comfortable for the patient. The present invention provides an adjustable food intake restriction device which is easy to adjust and does not require the use of an injection needle for accomplishing post-operation adjustments of the stoma opening.
In accordance with the invention a new food intake restriction device is provided for forming a stoma opening in the stomach or esophagus of a patient, comprising: an elongated restriction member, formed into at least a substantially closed loop around the stomach or the esophagus, the loop defining a restriction opening; a controllable adjustment device which adjusts the restriction member in the loop to change the size of the restriction opening; and a wireless remote control means for controlling the adjustment device from outside the patient's body (i.e. in a non-invasive manner). Thus, the new device does not require use of an injection needle for later adjustments of said restriction opening, thereby eliminating the infection risk discussed above in connection with prior art food intake devices. [An injection port may be provided for enabling, normally a single, once-and-for-all, calibration of the amount of fluid in adjustment device if it utilizes pneumatic or hydraulic components.] Furthermore, the use of the wireless remote control of the new device for controlling the adjustment device is comfortable for the patient.
In accordance with a broad aspect of the invention, the wireless remote control means comprises separate signal transmitting means and signal receiving means, the receiving means for controlling the adjustment device in response to signals received from the signal transmitting means. The remote control means comprises a motor for operating the adjustment device and an energizer unit for providing energy. The signal receiving means comprises a control unit adapted to power the motor with energy provided by the energizer unit in response to signals received from the signal transmitting means. Any known or conventional signal transmitting or receiving device that is suitable for use with a human or mammal patient may be provided s the signal transmitting or receiving means.
The invention also relates to a method of treating morbid obesity, comprising: (a) surgically implanting in the abdomen of a patient with morbid obesity a food intake restriction device which forms a stoma opening in the stomach or esophagus, by forming an elongated restriction member (e.g. of bio-compatible material, or covered with bio-compatible material) into at least a substantially closed loop around the stomach or the esophagus of the patient, the loop defining a restriction opening; and then (b) when necessary for the patient's health or desired progress, in a non-invasive procedure, using a wireless remote control device to adjust the restriction member to change the size of the restriction opening. In the method (a) may be practiced in part by implanting an electric motor which is part of an adjustment device for acting on the restriction member to control the size of the restriction opening; and (b) may be practiced by transmitting electromagnetic wave signals from outside the patient's body to inside the patient's body, and ultimately transforming the electromagnetic wave signals into electrical energy for powering the motor.
In the method, (a) may be practiced using laparoscopic techniques, e.g. (i) inflating the patient's abdomen with gas by penetration of the patient's skin, (ii) introducing at least two laparoscopic trocars into the abdomen to introduce the elongated restriction member and one or more medical instruments, and then (iii) forming the elongated restriction member into the at least substantially closed loop. Further, (b) may be practiced by sending electromagnetic waves through the skin into the abdomen, and in the abdomen transforming the waves into an electric current which is used to adjust the restriction member.
The motor may be any type of motor, such as a pneumatic, hydraulic or electric motor, and the energizer unit may power the motor with pressurized gas or liquid, or electrical energy, depending on the type of motor. Where the motor is an electric motor, it may power pneumatic or hydraulic equipment.
In accordance with a first particular embodiment of the invention, the energizer unit comprises a power supply and the control unit powers the motor with energy from the power supply. Preferably, the power supply is an electric power supply, such as a battery, and the motor is an electric motor. In this case, the battery also continuously powers the circuitry of the signal receiving means between adjustment operations, in order to keep the signal receiving means prepared for receiving signals transmitted from the signal transmitting means.
In accordance with a second, preferred, particular embodiment of the invention, the motor is an electric motor, the signal transmitting means transmits electromagnetic wave signals and the energizer unit draws radiant energy from the electromagnetic wave signals as they are transmitted to the signal receiving means and transfers the radiant energy into electric energy for powering the electric motor. This embodiment is particularly simple and does not require any recurrent invasive measures for exchanging empty power supplies, such as batteries, that is required in the first embodiment described above. This second embodiment is only practicable if the adjustment device is of a type that requires very little power for its operation, because in practice the electromagnetic wave signals transmitted in this connection are of low power.
To expand the field of application of the second preferred embodiment to adjustment devices of the type that require more, but still relatively low, power for operation, the energizer unit advantageously comprises a rechargeable electric power supply for storing the electric energy and the control unit is adapted to power the electric motor with energy from the rechargeable electric power supply in response to signals received from the signal transmitting means. In an initial charging step the rechargeable power supply can be charged over a relatively long time (e.g. a few seconds up to a half hour) without powering the electric motor. In a following operating step, when the power supply has been charged with sufficient energy, the control unit powers the electric motor with energy from the charged power supply to operate the adjustment device, so that a desired change of the patient's stoma opening is achieved. If the capacity of the power supply is significant to achieve the necessary adjustment in one single operating step, the above steps may conveniently be repeated until the desired adjustment is achieved.
The electric power supply suitably comprises an inexpensive simple capacitor. In this case, the electric motor may be a stepping motor.
In accordance with a third particular embodiment of the invention, the energizer unit comprises a battery, an electrically operable switch for connecting the battery to the signal receiving means in an "on" mode when the switch is powered and to keep the battery disconnected from the signal receiving means in a "standby" mode when the switch is unpowered, and a rechargeable electric power supply for powering the switch. The control unit powers the electric motor with energy from the battery in response to signals received from the signal transmitting means, when the switch is in its "on" mode. Advantageously, the signal transmitting means transmits electromagnetic wave signals and the energizer unit draws radiant energy from the electromagnetic wave signals as they are transmitted to the signal receiving means and transfers the radiant energy into a current for charging the rechargeable electric power supply, which suitably is a capacitor. This energy is then used to change the switch from "off" (standby mode) to "on". This embodiment is suited for adjustment devices of the type that require relatively high power for their operation and has the advantage that the electronic circuitry of the signal receiving means does not have to be powered by the battery between adjustment operations, as is the case in the above described first embodiment of the invention. As a result, the life-time of the battery can be significantly prolonged.
In the above-described second and third embodiments of the invention in which the energizer unit draws radiant energy from electromagnetic wave signals, the energizer unit suitably comprises a coil connected to the signal receiving means for inducing an alternating current as electromagnetic wave signals are transmitted through the coil to the signal receiving means, and a rectifier for rectifying the alternating current. The rectified current is used for charging the rechargeable power source, for instance a capacitor.
Although the above-described embodiments of the invention may very well be implemented in connection with the prior types of gastric banding devices discussed above, in which the adjustment device comprises an inflatable cavity of a restriction member, it is preferred to use an elongated restriction member which is non-inflatable, in order to avoid the risk of fluid leaking from the cavity. Furthermore, it is preferred to use an adjustment device which is designed to mechanically adjust the non-inflatable restriction member, such as shown in a copending application entitled "Mechanical Food Intake Restriction Device" filed on the same date as this application (attorney docket 2333-11), the disclosure of which is hereby incorporated by reference herein.
It is the primary object of the present invention to provide an advantageous yet relatively simple assembly and method for treating morbid obesity in a substantially non-invasive manner after initial surgical implantation of a restriction member. This and other objects will become clear from the detailed description and from the appended claims.